for (Entity e : p.getNearbyEntities(12,12,12)) {
                if (e instanceof Player) {
                    Player inFaction = (Player)e;
                    //Check if that player is in the faction
                    //IF they are
                    inFaction.addPotionEffect(new PotionEffect(PotionEffectType.INCREASE_DAMAGE,20*8,0));

                }
            }